Photo mapping, a popular mapping technique, can be a great timesaver - it can be far quicker taking photos of street signs or points of interest than either to write it down, typing on a smartphone, or using waypointing on a GPS gadget. What's more, smartphones and cameras can often add GPS coordinates, making it easy to match up the photos to the exact position they were taken.

Simple photo mapping

Use your camera to help you remember stuff. It can be as simple as that!

You don't need to use GPS and other advanced tricks described on this page. This is particularly true if you're in an area with good bing coverage (makes it a lot easier to get things in the right place) and if you have a good memory for this kind of thing. You'll need to remember the path you walked and the direction you were facing when you took the photos. To aid your memory it's always a good idea to input map data as soon as possible after collecting it. Also the more photos you take the better. If an area of one photo is visible in the previous photo, it makes it easier to orientate when you're looking back over them.

Orientation

Even if you have a GPS track, it can be difficult to determine the way you were facing when taking a photograph. You can develop your own tricks to solve these problems, but here's one approach: Simply rotate the camera: landscape pictures for what's ahead, portrait-size for infos about the way you just came from and a rotation of +/- 45° for what is on the right/left of the road. Pretty low-tech, but sufficient most of the time. You can also work out orientation using the angle of the sunlight in the pictures.

Geo-located photos

Smartphones and some cameras come with in-built GPS (and some GPS units come with in-built camera) so these devices will typically write geolocation data to the image file's metadata (EXIF) each time the shutter is snapped. This is very easy with a smartphone, although you may need to enable it. It makes things much easier. Tools such as JOSM will generally use this geolocation metadata.

Time synchronizing

What if you're using a camera without GPS? You might work with two separate gadgets, a camera and GPS unit. Digital cameras add the date and time to each photo (in the EXIF data), and a GPS tracklog will allow you to correlate by time, matching up the photos to the exact position they were taken. See JOSM/Photomapping if you want the photos to display in the proper location in JOSM, or see Geotagging Source Photos if you want to add geo-tags to photos that don't have them.

Integration with JOSM

Tagging and storage

If you want to tag an object (node, way etc) to show that you positioned it using a photograph and not GPS data (perhaps a fence you didn't walk along running directly between two places already on the map), use source=photograph. If, more commonly, it's the name of the object that you got from the photo (e.g. a street name), use source:name=photograph. Similarly, for road numbers (e.g. ref=A305), use source:ref=photograph.

There's nowhere within the OSM project for the photos themselves to be stored. If you upload them to a website such as Flickr, you can use e.g. source_ref=http://example.com/123.jpg (or source_ref:name=* or source_ref:ref=*) to link the photo to the object.

If you're using the Annotation Presets with JOSM, it'll suggest the right tag at the right time, and you won't need to worry about which one is which!

Other Software

EXIF data showing creation time

Geosetter can display photos on a variety of map backgrounds (Google, OSM, Mapbox) for an individual image or a folder of photos using a GPS tracklog and a GPS time calibration photograph for correlation. It uses ExifTool to write the corrected times and coordinates to the EXIF header. It can also look up locations (country, county, city, etc.) and optionally write that data to the EXIF header.

Seth Golub's geocoding scripts do pretty much the same thing, but write the data into the EXIF section of the JPEGs using exiv2. The scripts also provide a more usable command line interface to exiv2 for reading and writing geographic data to/from EXIF headers. (Uses the Google Maps API which is now defunct.)

More software and information about writing location in the pictures' metadata can be found on the Geotagging Source Photos wiki page.

Some Nokia camera phones do not include date information in EXIF headers, causing JOSM and other tools to fail. The date and time can be copied from the file creation time using the useful Perl library and command-line application ExifTool : $ exiftool -P '-FileModifyDate>DateTimeOriginal' *.jpg

For Linux users there is GPSCorrelate which has command line and GUI apps and is available in most repositories.

Also there is GPSPrune, a java-based cross-platform application which can correlate photos manually or automatically using timestamps (from GPX, KML or text files). It can output the photos in a KMZ file or it can use ExifTool to write the coordinates to the JPEG files.

A little tool to compute the -geosync parameter for ExifTool given a photo of an accurate time source, is found here.

Websites/projects about geolocating photos

Websites/projects as (free) services:

Flickr, the photo sharing site, supports special OSM "machine tags". If it's a photo of an OSM object you can add tags such as osm:way=123456 or osm:node=654321 and Flickr will link to the data browser page. We also have a normal 'openstreetmap' tag and a group.

OpenStreetCam, project to upload geotagged images and put them on openstreetmap layers. Even if you don't have any images yourself, you can help by moderating existing images!

Mapknitter (mapknitter.org), Public Lab's browser-based image stitching program, supports automatic or manual placement of aerial photos and exports them as GeoTIFF, TMS, or a basic JPG.

Pic4Carto, an efficient street pictures viewer for mapping. It combines pictures from several sources (Wikimedia Commons, Flickr, Mapillary, OpenStreetCam) and shows them all in a simple user interface. Website.

MapPIN'on OSM, introducing system of geotagged photos. The website is designed as very simple in order to introduce millions of photos. This server doesn't hold any photos. Those photos are uploaded on each author's blogs and just linked to "MapPIN'on OSM" by RSSes. Seems to be defunct (except for the Ads?).

OpenStreetPhoto. Somewhat misnamed project. Mostly working on various ideas for gathering aerial imagery (quadcopters) but some work on OCRing of street-level imagery. Seemed more active in 2009, then merged to OpenStreetView.